Warm or cold, the bottled Guinness is a completly different drink to the draft. The roasted flavour is really to the fore.
The Large bottle of Guinness Extra Stout is very popular here alright. Off the shelf being the 'proper' way to drink it.
As Séan said, my wife used to work in one of the local pubs here. A traditional shop in the front, pub in the back arrangement.
Their large bottles came in four different temperatures:
From the shelf; from the crate; from the store; and from the fridge.
The Guinness from the crate had just been brought in from the store, and were ideal temperature. To order a bottle from the store out the back you had to be a regular for at least 90 years, it seems.